The prior art as exemplified by the patents listed below show syringe assemblies for dispensing injectable medicaments which generally comprise an elongated, hollow barrel having luer-type fitting at the discharge end to mount a needle or cannula and a plunger rod which mounts a plunger usually made of rubber has radially outwardly projecting lugs or ribs which engage the barrel interior side wall during activation of the plunger rod axially in the barrel during filling of the syringe or activation of the plunger in an injection cycle. Even though these syringes are generally suitable for the purposes, it is been found that in some instances they are relatively expensive to manufacture by reason of the tolerances required to obtain the desired seal between the plunger ribs and the barrel and to prevent bypass or leakage of the medication during an injection stroke and the desired easy movement of the plunger when activating the same. It has been found that even where tolerances are controlled, leakage and ease of activation of the plunger are problematic.